On the Correlation Between Fatigue Striation Spacing and Crack Growth Rate: A Three-Dimensional (3-D) X-ray Synchrotron Tomography Study

Abstract

In situ three-dimensional (3-D) X-ray synchrotron tomography of fatigue crack growth was conducted in a 7075-T6 aluminum alloy. Local measurements of da/dN were possible with the 3-D data sets obtained from tomography. A comparison with fatigue striation spacings obtained from scanning electron microscopy of the fracture surfaces yielded excellent correlation with da/ dN obtained from tomography. The X-ray tomography technique can be used to obtain a highly accurate and representative measurements of crack growth locally in the microstructure of the material.

In situ experimental techniques to study the mechanical behavior of materials using X-ray synchrotron tomography

“…Using the second loading stage shown in Figure 3, in situ fatigue crack growth tomography was performed on AA7075-T651 samples [12,13]. The fatigue crack growth rates obtained from these experiments [12,15] were comparable to published data by others [21].…”

“…More recently, in situ mechanical testing has become more attractive, as a means of visualizing and quantifying microstructural changes as a function of time. Experiments under tension [8][9][10], cyclic loading [11][12][13][14], corrosion-fatigue [15], and creep [16,17] have been conducted.…”

Effect of microstructure on high cycle fatigue behavior of Ti–5Al–5Mo–5V–3Cr–1Zr titanium alloy

“…Previous researchers [27,28] suggested that the correlation between fatigue striation spacing and the crack growth rate (CGR) is one-to-one correlation in ductile materials, especially in stable growth regions. According to this view, the CGR of LM will be larger than that of BM.…”

Data intensive science at synchrotron based 3D x-ray imaging facilities

“…More complex experiments are also possible, such as fatigue crack deformation mechanisms under cyclic loading and in corrosive environments [2]. In another set of experiments using 3D x-ray diffraction it was possible to quantify the effect of crystallographic orientations on crack growth.…”